Summary auto-generated
This study examines how different chemical and physical treatments inactivate reovirus particles by analyzing changes in particle density, polypeptide composition, and ultrastructure. Researchers treated three reovirus serotypes with agents including heat, pH 11, guanidine-HCl, SDS, phenol, and ethanol. Results showed that each agent had distinct effects: pH 11 and heat specifically removed the σ1 protein (cell attachment factor) from certain serotypes, reducing their ability to adsorb to cells. SDS removed the σ3 outer capsid protein and altered particle structure. Guanidine-HCl caused viral aggregation while maintaining polypeptide composition. Phenol and ethanol induced aggregation without detectable polypeptide loss. These biochemical findings complement genetic studies showing that viral sensitivity to these agents is determined by specific genes. The study demonstrates that chemical inactivation mechanisms are highly specific and involve disruption of distinct viral components, providing insights into reovirus capsid structure and function.
Key findings
- pH 11 and heat remove the σ1 cell attachment protein from reovirus, reducing viral adsorption to cells and explaining loss of infectivity
- SDS specifically removes the σ3 outer capsid protein and increases particle density, causing visible ultrastructural alterations
- Guanidine-HCl inactivates virus by causing aggregation through σ1 protein denaturation while maintaining full polypeptide composition
- Phenol and ethanol induce viral particle aggregation without causing detectable changes to polypeptide composition, indicating their mechanism involves structural destabilization
- Different inactivating agents target specific viral proteins and mechanisms, confirming genetic predictions that viral serotype-specific resistance is determined by distinct genes
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Abstract
We have examined the effects of heat and several chemical inactivating agents on the buoyant density, particle-associated polypeptides and ultrastructure of reovirus particles. Treatment at pH 11 removed polypeptide σ1 from the outer capsid of reovirus type 2 but not from type 1; resultant particles were unchanged in their buoyant density and morphology. Treatment of reovirus types 2 and 3 with 2.5 M-guanidine-HCl produced particles with unchanged polypeptide content but an increased buoyant density, and caused aggregation of type 3 but not type 2. Treatment with 1% SDS removed polypeptide σ3 from both types 1 and 2 and increased the buoyant density of the virus particles. The outer capsid of SDS-treated virions was greatly altered and often indistinct. Treatment of type 3 with either 1% phenol or 33% ethanol produced particles that had a full complement of polypeptides, were unaltered in buoyant density, but were greatly aggregated. Thus, these inactivating agents affect reovirus particles in specific and distinct ways. The differential effects of such treatments can thus be used to study the structure and function of the reovirus capsid components.